Commit Graph

86 Commits

Author SHA1 Message Date
David E. O'Brien
677b542ea2 Use __FBSDID(). 2003-06-11 00:56:59 +00:00
John Baldwin
5e26dcb560 - Add a td_pflags field to struct thread for private flags accessed only by
curthread.  Unlike td_flags, this field does not need any locking.
- Replace the td_inktr and td_inktrace variables with equivalent private
  thread flags.
- Move TDF_OLDMASK over to the private flags field so it no longer requires
  sched_lock.
2003-06-09 17:38:32 +00:00
John Baldwin
64cc6a13e7 - Push down Giant around vnode operations in ktrace().
- Mark the ktrace() and utrace() syscalls as being MP safe.
- Validate the facs argument to ktrace() prior to doing any vnode
  operations or acquiring any locks.
- Share lock the proctree lock over the entire section that calls
  ktrsetchildren() and ktrops().  We already did this for process groups.
  Doing it for the process case closes a small race where a process might
  go away after we look it up.  As a result of this, ktrstchildren() now
  just asserts that the proctree lock is locked rather than acquiring the
  lock itself.
- Add some missing comments to #else and #endif.
2003-04-25 19:59:35 +00:00
John Baldwin
75768576cc Add a new userland-visible ktrace flag KTR_DROP and an internal ktrace flag
KTRFAC_DROP to track instances when ktrace events are dropped due to the
request pool being exhausted.  When a thread tries to post a ktrace event
and is unable to due to no available ktrace request objects, it sets
KTRFAC_DROP in its process' p_traceflag field.  The next trace event to
successfully post from that process will set the KTR_DROP flag in the
header of the request going out and clear KTRFAC_DROP.

The KTR_DROP flag is the high bit in the type field of the ktr_header
structure.  Older kdump binaries will simply complain about an unknown type
when seeing an entry with KTR_DROP set.  Note that KTR_DROP being set on a
record in a ktrace file does not tell you anything except that at least one
event from this process was dropped prior to this event.  The user has no
way of knowing what types of events were dropped nor how many were dropped.

Requested by:	phk
2003-03-13 18:31:15 +00:00
John Baldwin
a5881ea55a - Cache a reference to the credential of the thread that starts a ktrace in
struct proc as p_tracecred alongside the current cache of the vnode in
  p_tracep.  This credential is then used for all later ktrace operations on
  this file rather than using the credential of the current thread at the
  time of each ktrace event.
- Now that we have multiple ktrace-related items in struct proc that are
  pointers, rename p_tracep to p_tracevp to make it less ambiguous.

Requested by:	rwatson (1)
2003-03-13 18:24:22 +00:00
Warner Losh
a163d034fa Back out M_* changes, per decision of the TRB.
Approved by: trb
2003-02-19 05:47:46 +00:00
Alfred Perlstein
44956c9863 Remove M_TRYWAIT/M_WAITOK/M_WAIT. Callers should use 0.
Merge M_NOWAIT/M_DONTWAIT into a single flag M_NOWAIT.
2003-01-21 08:56:16 +00:00
Scott Long
316ec49abd Some kernel threads try to do significant work, and the default KSTACK_PAGES
doesn't give them enough stack to do much before blowing away the pcb.
This adds MI and MD code to allow the allocation of an alternate kstack
who's size can be speficied when calling kthread_create.  Passing the
value 0 prevents the alternate kstack from being created.  Note that the
ia64 MD code is missing for now, and PowerPC was only partially written
due to the pmap.c being incomplete there.
Though this patch does not modify anything to make use of the alternate
kstack, acpi and usb are good candidates.

Reviewed by:	jake, peter, jhb
2002-10-02 07:44:29 +00:00
Poul-Henning Kamp
50c2233141 Plug memory leaks.
Detected by:	FlexeLint
Approved by:	jhb
2002-09-30 19:19:47 +00:00
John Baldwin
c9e7d28e26 - Change utrace ktrace events to malloc the work buffer before getting a
request structure.
- Re-optimize the case of utrace being disabled by doing an explicit
  KTRPOINT check instead of relying on the one in ktr_getrequest() so that
  we don't waste time on a malloc in the non-tracing case.
- Change utrace() to return an error if the copyin() fails.  Before it
  would just ignore the request but still return success.  This last is
  a change in behavior and can be backed out if necessary.
2002-09-11 21:00:56 +00:00
John Baldwin
1d3ab18279 Remove support for synchronous ktrace requests now that none exist anymore.
They were an ugly, gross hack.
2002-09-11 20:58:10 +00:00
John Baldwin
b92584a689 - Change ktrace genio events to only copy up to ktr_geniosize bytes of a
transfer to a malloc'd buffer and use that bufer for the ktrace event.
  This means that genio ktrace events no longer need to be synchronous.
- Now that ktr_buffer isn't overloaded to sometimes point to a cached uio
  pointer for genio requests and always points to a malloc'd buffer if not
  NULL, free the buffer in ktr_freerequest() instead of in
  ktr_writerequest().  This closes a memory leak for ktrace events that
  used a malloc'd buffer that had their vnode ripped out from under them
  while they were on the todo list.

Suggested by:	bde (1, in principle)
2002-09-11 20:56:05 +00:00
John Baldwin
12301fc3c7 - Add a kern.ktrace sysctl node.
- Rename kern.ktrace_request_pool tunable/sysctl to
  kern.ktrace.request_pool.
- Add a variable to control the max amount of data to log for genio events.
  This variable is tunable via the tunable/sysctl kern.ktrace.genio_size
  and defaults to one page.
2002-09-11 20:49:55 +00:00
John Baldwin
4b3aac3d4e Change namei and syscall ktrace events to malloc work buffers before
obtaining a ktr_request structure from the free pool so we can avoid
starving other threads of ktr_request structures.
2002-09-11 20:46:50 +00:00
Robert Watson
177142e458 Pass active_cred and file_cred into the MAC framework explicitly
for mac_check_vnode_{poll,read,stat,write}().  Pass in fp->f_cred
when calling these checks with a struct file available.  Otherwise,
pass NOCRED.  All currently MAC policies use active_cred, but
could now offer the cached credential semantic used for the base
system security model.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, NAI Labs
2002-08-19 19:04:53 +00:00
Robert Watson
7f724f8b51 Break out mac_check_vnode_op() into three seperate checks:
mac_check_vnode_poll(), mac_check_vnode_read(), mac_check_vnode_write().
This improves the consistency with other existing vnode checks, and
allows policies to avoid implementing switch statements to determine
what operations they do and do not want to authorize.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, NAI Labs
2002-08-19 16:43:25 +00:00
John Baldwin
fbd140c786 If we fail to write to a vnode during a ktrace write, then we drop all
other references to that vnode as a trace vnode in other processes as well
as in any pending requests on the todo list.  Thus, it is possible for a
ktrace request structure to have a NULL ktr_vp when it is destroyed in
ktr_freerequest().  We shouldn't call vrele() on the vnode in that case.

Reported by:	bde
2002-08-01 13:35:38 +00:00
Robert Watson
467a273ca0 Introduce support for Mandatory Access Control and extensible
kernel access control.

Instrument the ktrace write operation so that it invokes the MAC
framework's vnode write authorization check.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, NAI Labs
2002-08-01 01:07:03 +00:00
Alfred Perlstein
7f05b0353a More caddr_t removal, make fo_ioctl take a void * instead of a caddr_t. 2002-06-29 01:50:25 +00:00
John Baldwin
ea3fc8e4cd Overhaul the ktrace subsystem a bit. For the most part, the actual vnode
operations to dump a ktrace event out to an output file are now handled
asychronously by a ktrace worker thread.  This enables most ktrace events
to not need Giant once p_tracep and p_traceflag are suitably protected by
the new ktrace_lock.

There is a single todo list of pending ktrace requests.  The various
ktrace tracepoints allocate a ktrace request object and tack it onto the
end of the queue.  The ktrace kernel thread grabs requests off the head of
the queue and processes them using the trace vnode and credentials of the
thread triggering the event.

Since we cannot assume that the user memory referenced when doing a
ktrgenio() will be valid and since we can't access it from the ktrace
worker thread without a bit of hassle anyways, ktrgenio() requests are
still handled synchronously.  However, in order to ensure that the requests
from a given thread still maintain relative order to one another, when a
synchronous ktrace event (such as a genio event) is triggered, we still put
the request object on the todo list to synchronize with the worker thread.
The original thread blocks atomically with putting the item on the queue.
When the worker thread comes across an asynchronous request, it wakes up
the original thread and then blocks to ensure it doesn't manage to write a
later event before the original thread has a chance to write out the
synchronous event.  When the original thread wakes up, it writes out the
synchronous using its own context and then finally wakes the worker thread
back up.  Yuck.  The sychronous events aren't pretty but they do work.

Since ktrace events can be triggered in fairly low-level areas (msleep()
and cv_wait() for example) the ktrace code is designed to use very few
locks when posting an event (currently just the ktrace_mtx lock and the
vnode interlock to bump the refcoun on the trace vnode).  This also means
that we can't allocate a ktrace request object when an event is triggered.
Instead, ktrace request objects are allocated from a pre-allocated pool
and returned to the pool after a request is serviced.

The size of this pool defaults to 100 objects, which is about 13k on an
i386 kernel.  The size of the pool can be adjusted at compile time via the
KTRACE_REQUEST_POOL kernel option, at boot time via the
kern.ktrace_request_pool loader tunable, or at runtime via the
kern.ktrace_request_pool sysctl.

If the pool of request objects is exhausted, then a warning message is
printed to the console.  The message is rate-limited in that it is only
printed once until the size of the pool is adjusted via the sysctl.

I have tested all kernel traces but have not tested user traces submitted
by utrace(2), though they should work fine in theory.

Since a ktrace request has several properties (content of event, trace
vnode, details of originating process, credentials for I/O, etc.), I chose
to drop the first argument to the various ktrfoo() functions.  Currently
the functions just assume the event is posted from curthread.  If there is
a great desire to do so, I suppose I could instead put back the first
argument but this time make it a thread pointer instead of a vnode pointer.

Also, KTRPOINT() now takes a thread as its first argument instead of a
process.  This is because the check for a recursive ktrace event is now
per-thread instead of process-wide.

Tested on:	i386
Compiles on:	sparc64, alpha
2002-06-07 05:32:59 +00:00
John Baldwin
f44d9e24fb Change p_can{debug,see,sched,signal}()'s first argument to be a thread
pointer instead of a proc pointer and require the process pointed to
by the second argument to be locked.  We now use the thread ucred reference
for the credential checks in p_can*() as a result.  p_canfoo() should now
no longer need Giant.
2002-05-19 00:14:50 +00:00
John Baldwin
ba626c1db2 Lock proctree_lock instead of pgrpsess_lock. 2002-04-16 17:11:34 +00:00
John Baldwin
a7ff744350 - Change the first argument of ktrcanset(), ktrsetchildren(), and ktrops()
to a thread pointer so that ktrcanset() can use td_ucred.
- Add some proc locking to partially protect p_tracep and p_traceflag.
2002-04-13 22:54:18 +00:00
John Baldwin
44731cab3b Change the suser() API to take advantage of td_ucred as well as do a
general cleanup of the API.  The entire API now consists of two functions
similar to the pre-KSE API.  The suser() function takes a thread pointer
as its only argument.  The td_ucred member of this thread must be valid
so the only valid thread pointers are curthread and a few kernel threads
such as thread0.  The suser_cred() function takes a pointer to a struct
ucred as its first argument and an integer flag as its second argument.
The flag is currently only used for the PRISON_ROOT flag.

Discussed on:	smp@
2002-04-01 21:31:13 +00:00
Alfred Perlstein
4d77a549fe Remove __P. 2002-03-19 21:25:46 +00:00
Alfred Perlstein
628abf6c69 Giant pushdown for read/write/pread/pwrite syscalls.
kern/kern_descrip.c:
Aquire Giant in fdrop_locked when file refcount hits zero, this removes
the requirement for the caller to own Giant for the most part.

kern/kern_ktrace.c:
Aquire Giant in ktrgenio, simplifies locking in upper read/write syscalls.

kern/vfs_bio.c:
Aquire Giant in bwillwrite if needed.

kern/sys_generic.c
Giant pushdown, remove Giant for:
   read, pread, write and pwrite.
readv and writev aren't done yet because of the possible malloc calls
for iov to uio processing.

kern/sys_socket.c
Grab giant in the socket fo_read/write functions.

kern/vfs_vnops.c
Grab giant in the vnode fo_read/write functions.
2002-03-15 08:03:46 +00:00
John Baldwin
6bd7ad69a1 Add a comment about an unlocked access to p_ucred that will go away in
the near future.
2002-02-27 19:10:50 +00:00
John Baldwin
a854ed9893 Simple p_ucred -> td_ucred changes to start using the per-thread ucred
reference.
2002-02-27 18:32:23 +00:00
Seigo Tanimura
f591779bb5 Lock struct pgrp, session and sigio.
New locks are:

- pgrpsess_lock which locks the whole pgrps and sessions,
- pg_mtx which protects the pgrp members, and
- s_mtx which protects the session members.

Please refer to sys/proc.h for the coverage of these locks.

Changes on the pgrp/session interface:

- pgfind() needs the pgrpsess_lock held.

- The caller of enterpgrp() is responsible to allocate a new pgrp and
  session.

- Call enterthispgrp() in order to enter an existing pgrp.

- pgsignal() requires a pgrp lock held.

Reviewed by:	jhb, alfred
Tested on:	cvsup.jp.FreeBSD.org
		(which is a quad-CPU machine running -current)
2002-02-23 11:12:57 +00:00
Matthew Dillon
79deba82cd Fix ktrace enablement/disablement races that can result in a vnode
ref count panic.

Bug noticed by:	ps
Reviewed by:	ps
MFC after:	1 day
2001-10-24 01:05:39 +00:00
Julian Elischer
b40ce4165d KSE Milestone 2
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.

Sorry john! (your next MFC will be a doosie!)

Reviewed by: peter@freebsd.org, dillon@freebsd.org

X-MFC after:    ha ha ha ha
2001-09-12 08:38:13 +00:00
Matthew Dillon
356861db03 Remove the MPSAFE keyword from the parser for syscalls.master.
Instead introduce the [M] prefix to existing keywords.  e.g.
MSTD is the MP SAFE version of STD.  This is prepatory for a
massive Giant lock pushdown.  The old MPSAFE keyword made
syscalls.master too messy.

Begin comments MP-Safe procedures with the comment:
/*
 * MPSAFE
 */
This comments means that the procedure may be called without
Giant held (The procedure itself may still need to obtain
Giant temporarily to do its thing).

sv_prepsyscall() is now MP SAFE and assumed to be MP SAFE
sv_transtrap() is now MP SAFE and assumed to be MP SAFE

ktrsyscall() and ktrsysret() are now MP SAFE (Giant Pushdown)
trapsignal() is now MP SAFE (Giant Pushdown)

Places which used to do the if (mtx_owned(&Giant)) mtx_unlock(&Giant)
test in syscall[2]() in */*/trap.c now do not.  Instead they
explicitly unlock Giant if they previously obtained it, and then
assert that it is no longer held to catch broken system calls.

Rebuild syscall tables.
2001-08-30 18:50:57 +00:00
Robert Watson
a0f75161f9 o Replace calls to p_can(..., P_CAN_xxx) with calls to p_canxxx().
The p_can(...) construct was a premature (and, it turns out,
  awkward) abstraction.  The individual calls to p_canxxx() better
  reflect differences between the inter-process authorization checks,
  such as differing checks based on the type of signal.  This has
  a side effect of improving code readability.
o Replace direct credential authorization checks in ktrace() with
  invocation of p_candebug(), while maintaining the special case
  check of KTR_ROOT.  This allows ktrace() to "play more nicely"
  with new mandatory access control schemes, as well as making its
  authorization checks consistent with other "debugging class"
  checks.
o Eliminate "privused" construct for p_can*() calls which allowed the
  caller to determine if privilege was required for successful
  evaluation of the access control check.  This primitive is currently
  unused, and as such, serves only to complicate the API.

Approved by:	({procfs,linprocfs} changes) des
Obtained from:	TrustedBSD Project
2001-07-05 17:10:46 +00:00
Robert Watson
b1fc0ec1a7 o Merge contents of struct pcred into struct ucred. Specifically, add the
real uid, saved uid, real gid, and saved gid to ucred, as well as the
  pcred->pc_uidinfo, which was associated with the real uid, only rename
  it to cr_ruidinfo so as not to conflict with cr_uidinfo, which
  corresponds to the effective uid.
o Remove p_cred from struct proc; add p_ucred to struct proc, replacing
  original macro that pointed.
  p->p_ucred to p->p_cred->pc_ucred.
o Universally update code so that it makes use of ucred instead of pcred,
  p->p_ucred instead of p->p_pcred, cr_ruidinfo instead of p_uidinfo,
  cr_{r,sv}{u,g}id instead of p_*, etc.
o Remove pcred0 and its initialization from init_main.c; initialize
  cr_ruidinfo there.
o Restruction many credential modification chunks to always crdup while
  we figure out locking and optimizations; generally speaking, this
  means moving to a structure like this:
        newcred = crdup(oldcred);
        ...
        p->p_ucred = newcred;
        crfree(oldcred);
  It's not race-free, but better than nothing.  There are also races
  in sys_process.c, all inter-process authorization, fork, exec, and
  exit.
o Remove sigio->sio_ruid since sigio->sio_ucred now contains the ruid;
  remove comments indicating that the old arrangement was a problem.
o Restructure exec1() a little to use newcred/oldcred arrangement, and
  use improved uid management primitives.
o Clean up exit1() so as to do less work in credential cleanup due to
  pcred removal.
o Clean up fork1() so as to do less work in credential cleanup and
  allocation.
o Clean up ktrcanset() to take into account changes, and move to using
  suser_xxx() instead of performing a direct uid==0 comparision.
o Improve commenting in various kern_prot.c credential modification
  calls to better document current behavior.  In a couple of places,
  current behavior is a little questionable and we need to check
  POSIX.1 to make sure it's "right".  More commenting work still
  remains to be done.
o Update credential management calls, such as crfree(), to take into
  account new ruidinfo reference.
o Modify or add the following uid and gid helper routines:
      change_euid()
      change_egid()
      change_ruid()
      change_rgid()
      change_svuid()
      change_svgid()
  In each case, the call now acts on a credential not a process, and as
  such no longer requires more complicated process locking/etc.  They
  now assume the caller will do any necessary allocation of an
  exclusive credential reference.  Each is commented to document its
  reference requirements.
o CANSIGIO() is simplified to require only credentials, not processes
  and pcreds.
o Remove lots of (p_pcred==NULL) checks.
o Add an XXX to authorization code in nfs_lock.c, since it's
  questionable, and needs to be considered carefully.
o Simplify posix4 authorization code to require only credentials, not
  processes and pcreds.  Note that this authorization, as well as
  CANSIGIO(), needs to be updated to use the p_cansignal() and
  p_cansched() centralized authorization routines, as they currently
  do not take into account some desirable restrictions that are handled
  by the centralized routines, as well as being inconsistent with other
  similar authorization instances.
o Update libkvm to take these changes into account.

Obtained from:	TrustedBSD Project
Reviewed by:	green, bde, jhb, freebsd-arch, freebsd-audit
2001-05-25 16:59:11 +00:00
Mark Murray
fb919e4d5a Undo part of the tangle of having sys/lock.h and sys/mutex.h included in
other "system" header files.

Also help the deprecation of lockmgr.h by making it a sub-include of
sys/lock.h and removing sys/lockmgr.h form kernel .c files.

Sort sys/*.h includes where possible in affected files.

OK'ed by:	bde (with reservations)
2001-05-01 08:13:21 +00:00
John Baldwin
33a9ed9d0e Change the pfind() and zpfind() functions to lock the process that they
find before releasing the allproc lock and returning.

Reviewed by:	-smp, dfr, jake
2001-04-24 00:51:53 +00:00
John Baldwin
1005a129e5 Convert the allproc and proctree locks from lockmgr locks to sx locks. 2001-03-28 11:52:56 +00:00
Robert Watson
91421ba234 o Move per-process jail pointer (p->pr_prison) to inside of the subject
credential structure, ucred (cr->cr_prison).
o Allow jail inheritence to be a function of credential inheritence.
o Abstract prison structure reference counting behind pr_hold() and
  pr_free(), invoked by the similarly named credential reference
  management functions, removing this code from per-ABI fork/exit code.
o Modify various jail() functions to use struct ucred arguments instead
  of struct proc arguments.
o Introduce jailed() function to determine if a credential is jailed,
  rather than directly checking pointers all over the place.
o Convert PRISON_CHECK() macro to prison_check() function.
o Move jail() function prototypes to jail.h.
o Emulate the P_JAILED flag in fill_kinfo_proc() and no longer set the
  flag in the process flags field itself.
o Eliminate that "const" qualifier from suser/p_can/etc to reflect
  mutex use.

Notes:

o Some further cleanup of the linux/jail code is still required.
o It's now possible to consider resolving some of the process vs
  credential based permission checking confusion in the socket code.
o Mutex protection of struct prison is still not present, and is
  required to protect the reference count plus some fields in the
  structure.

Reviewed by:	freebsd-arch
Obtained from:	TrustedBSD Project
2001-02-21 06:39:57 +00:00
Alfred Perlstein
bdfa4f04d9 Don't use SCARG.
Pointed out by: bde
2001-01-08 07:22:06 +00:00
Alfred Perlstein
0bad156a91 Limit size of passed in data for utrace function.
Requested by: rwatson
Obtained from: NetBSD
2001-01-06 09:34:20 +00:00
Jake Burkholder
98f03f9030 Protect proc.p_pptr and proc.p_children/p_sibling with the
proctree_lock.

linprocfs not locked pending response from informal maintainer.

Reviewed by:	jhb, -smp@
2000-12-23 19:43:10 +00:00
Jake Burkholder
c0c2557090 - Change the allproc_lock to use a macro, ALLPROC_LOCK(how), instead
of explicit calls to lockmgr.  Also provides macros for the flags
  pased to specify shared, exclusive or release which map to the
  lockmgr flags.  This is so that the use of lockmgr can be easily
  replaced with optimized reader-writer locks.
- Add some locking that I missed the first time.
2000-12-13 00:17:05 +00:00
Jake Burkholder
553629ebc9 Protect the following with a lockmgr lock:
allproc
	zombproc
	pidhashtbl
	proc.p_list
	proc.p_hash
	nextpid

Reviewed by:	jhb
Obtained from:	BSD/OS and netbsd
2000-11-22 07:42:04 +00:00
Poul-Henning Kamp
46aa3347cb Convert all users of fldoff() to offsetof(). fldoff() is bad
because it only takes a struct tag which makes it impossible to
use unions, typedefs etc.

Define __offsetof() in <machine/ansi.h>

Define offsetof() in terms of __offsetof() in <stddef.h> and <sys/types.h>

Remove myriad of local offsetof() definitions.

Remove includes of <stddef.h> in kernel code.

NB: Kernelcode should *never* include from /usr/include !

Make <sys/queue.h> include <machine/ansi.h> to avoid polluting the API.

Deprecate <struct.h> with a warning.  The warning turns into an error on
01-12-2000 and the file gets removed entirely on 01-01-2001.

Paritials reviews by:   various.
Significant brucifications by:  bde
2000-10-27 11:45:49 +00:00
Jason Evans
62ae6c89ad Add KTR, a facility that logs kernel events in order to to facilitate
debugging.

Acquired from:	BSDi (BSD/OS)
Submitted by:	dfr, grog, jake, jhb
2000-09-07 01:29:44 +00:00
Robert Watson
387d2c036b o Centralize inter-process access control, introducing:
int p_can(p1, p2, operation, privused)

  which allows specification of subject process, object process,
  inter-process operation, and an optional call-by-reference privused
  flag, allowing the caller to determine if privilege was required
  for the call to succeed.  This allows jail, kern.ps_showallprocs and
  regular credential-based interaction checks to occur in one block of
  code.  Possible operations are P_CAN_SEE, P_CAN_SCHED, P_CAN_KILL,
  and P_CAN_DEBUG.  p_can currently breaks out as a wrapper to a
  series of static function checks in kern_prot, which should not
  be invoked directly.

o Commented out capabilities entries are included for some checks.

o Update most inter-process authorization to make use of p_can() instead
  of manual checks, PRISON_CHECK(), P_TRESPASS(), and
  kern.ps_showallprocs.

o Modify suser{,_xxx} to use const arguments, as it no longer modifies
  process flags due to the disabling of ASU.

o Modify some checks/errors in procfs so that ENOENT is returned instead
  of ESRCH, further improving concealment of processes that should not
  be visible to other processes.  Also introduce new access checks to
  improve hiding of processes for procfs_lookup(), procfs_getattr(),
  procfs_readdir().  Correct a bug reported by bp concerning not
  handling the CREATE case in procfs_lookup().  Remove volatile flag in
  procfs that caused apparently spurious qualifier warnigns (approved by
  bde).

o Add comment noting that ktrace() has not been updated, as its access
  control checks are different from ptrace(), whereas they should
  probably be the same.  Further discussion should happen on this topic.

Reviewed by:	bde, green, phk, freebsd-security, others
Approved by:	bde
Obtained from:	TrustedBSD Project
2000-08-30 04:49:09 +00:00
Kirk McKusick
f2a2857bb3 Add snapshots to the fast filesystem. Most of the changes support
the gating of system calls that cause modifications to the underlying
filesystem. The gating can be enabled by any filesystem that needs
to consistently suspend operations by adding the vop_stdgetwritemount
to their set of vnops. Once gating is enabled, the function
vfs_write_suspend stops all new write operations to a filesystem,
allows any filesystem modifying system calls already in progress
to complete, then sync's the filesystem to disk and returns. The
function vfs_write_resume allows the suspended write operations to
begin again. Gating is not added by default for all filesystems as
for SMP systems it adds two extra locks to such critical kernel
paths as the write system call. Thus, gating should only be added
as needed.

Details on the use and current status of snapshots in FFS can be
found in /sys/ufs/ffs/README.snapshot so for brevity and timelyness
is not included here. Unless and until you create a snapshot file,
these changes should have no effect on your system (famous last words).
2000-07-11 22:07:57 +00:00
Brian Feldman
9d1cfdce2a Change that &@!$# UIO_READ to be UIO_WRITE. I tested the ktrace stuff,
but somehow... pass the pointy hat, again!
2000-07-07 21:52:15 +00:00
Kirk McKusick
e6796b67d9 Move the truncation code out of vn_open and into the open system call
after the acquisition of any advisory locks. This fix corrects a case
in which a process tries to open a file with a non-blocking exclusive
lock. Even if it fails to get the lock it would still truncate the
file even though its open failed. With this change, the truncation
is done only after the lock is successfully acquired.

Obtained from:	 BSD/OS
2000-07-04 03:34:11 +00:00
Brian Feldman
42ebfbf227 Modify ktrace's general I/O tracing, ktrgenio(), to use a struct uio *
instead of a struct iovec * array and int len.  Get rid of stupidly trying
to allocate all of the memory and copyin()ing the entire iovec[], and
instead just do the proper VOP_WRITE() in ktrwrite() using a copy of
the struct uio that the syscall originally used.

This solves the DoS which could easily be performed; to work around the
DoS, one could also remove "options KTRACE" from the kernel.  This is
a very strong MFC candidate for 4.1.

Found by:	art@OpenBSD.org
2000-07-02 08:08:09 +00:00